Various transport structures for transporting tire wheels such as aluminum wheels have been proposed (for example, see Japanese Patent No. 3318120).
Japanese Patent No. 3318120 discloses a pallet including a placing surface having annular grooves corresponding to plural types of automobile wheels having different diameters. On the pallet, the annular grooves corresponding to the respective diameters are configured by annular grooves and other types of annular grooves planarly overlapped with each other. According to the pallet of Japanese Patent No. 3318120, the wheels are transported with the wheels being fitted into the annular grooves corresponding to diameters of the respective wheels. This avoids displacement of the wheels, and enables to transport and store plural types of wheels having different sizes.
Japanese Patent No. 3561875 discloses a technique by which each stage of tire wheels stacked in multiple stages on a pallet is sandwiched by two support-fixing members capable of avoiding horizontal movement of the tire wheels. With this technique, it is possible to stack the tire wheels in multiple stages on the pallet, while avoiding the horizontal movement of the tire wheels.
Incidentally, recently, there are demands for further improvement in efficiency of transportation and storage of automobile parts. Thus, also for the tire-wheel transport structure, there is a demand for a technique for transporting and storing a larger number of tire wheels more efficiently.